Some have even suggested zonal tax rebates/scales (Barnaby picked up on this recently).
I'm no constitutional lawyer, but why are the current zonal tax rebates legal under the constitution? Specifically,
51. The Parliament shall, subject to this Constitution, have power to make laws for the peace, order, and good government of the Commonwealth with respect to:
(ii.) Taxation; but so as not to discriminate between States or parts of States:



